JPH09152402A - Light scatterer measuring device - Google Patents

Abstract

(57) Abstract: It is possible to obtain the same positional resolution as when the light receiving device is brought into contact with the light receiving device while being separated from the sample. SOLUTION: A plurality of light receiving ends 12-1, 12-2, ... Are equidistantly arranged in order to receive the measurement light, which is transmitted while diffusing through the sample 2, from each measurement target point on the surface of the sample.
4 is fixed. Sample 2 and each light receiving end 12-1, 12
Between −2, ..., Convex lenses 10-1, 10 are provided as image forming optical systems for forming respective measurement points on the sample surface on the respective light receiving ends 12-1, 12-2 ,. -2, ... Are fixed to the holder 24. The output light diffused and transmitted through the sample 2 is simultaneously incident on and received by a large number of light receiving ends 12-1, 12-2, .... At this time, the points to be measured on the surface of the sample 2 are respectively corresponding to the light receiving ends 12-1, 12-2, ... by the lenses 10-1, 10-2 ,.
Is imaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a light-scattering sample such as a living body with measurement light in the near-infrared region, detects diffused / transmitted reflected light by the sample, and nondestructively collects information in an object. The present invention relates to a measuring device. Such a measuring device is used, for example, as a biological oxygen monitor or optical CT.

[0002]

2. Description of the Related Art Near-infrared rays in the range of 600 to 1200 nm have good permeability to living organisms and maintain sufficient intensity for measurement even after passing a distance of several cm in living organisms. Conveniently, since the absorption spectra of hemoglobin and cytochrome oxidase, which are important substances that reflect biological functions, exist in this wavelength range, this property of near-infrared light is utilized to eliminate biological functions. Invasive measurements are performed.

When measuring a living body by using diffused light such as optical CT, there are two methods: a method in which a light-transmitting and light-receiving device is placed in close contact with a sample, and a method in which it is placed away from the sample. As an example of the method of installing the light emitting and receiving device away from the sample,
A gantry including a light-transmitting and light-receiving part is rotated around the sample, and measurement data obtained by combining a number of light-transmitting and light-receiving points are obtained (see SPIE Vol. 1431, pp.284-293 (1991)). X-ray CT
As described above, since the sample or the detector can be relatively rotated, there is an advantage that a large number of light transmitting points and a large number of measurement target points can be scanned while using a small number of light transmitting and receiving portions.

On the other hand, in the method in which the light transmitting / receiving device is closely attached to the sample, the position resolution is improved (BME Vol. 8, No. 8, p.
p.4-13 (1994)). The method of bringing them into close contact is called the “contact method”, and since the light-transmitting and receiving device and the sample cannot be rotated relative to each other, it is necessary to use an optical fiber switching device equivalent to the rotation, which complicates the configuration. . In this reference, the position resolution is lowered due to the reflection and refraction of light on the surface of the living body when the measurement is performed away from the sample, but the contact method does not have such a problem and the position resolution is said to be improved.

According to the consideration of the present inventors, the reason why the position resolution is improved by the contact method is considered as follows. When the light-sending / receiving device is brought into close contact with the sample, as shown in FIG. 1, a light-sending point 4 for allowing the measuring light to enter the sample 2 as shown in FIG.
When the measurement target point 6 is determined, the contribution of each point in the sample 2 to the received light signal becomes a banana shape as shown by reference numeral 8, and it becomes thin near the light transmitting point 4 and the measurement target point 6. Is believed to have led to improved resolution. In any case, it is a fact that the position resolution is lowered when the light transmitting / receiving device is separated from the sample as compared with the contact method.

[0006]

The non-contact method is used when it is necessary to measure at least the probe provided with the light receiving device without contacting the sample such as a living body or when many data points are required. The object of the present invention is to obtain a positional resolution equivalent to that of the contact method while performing the measurement in the non-contact method when the device has a simple structure.

[0007]

According to the present invention, while the light receiving device is installed away from the measurement target point of a sample such as a light-scattering living body, the measurement target point is imaged one-to-one on the light receiving end of the light receiving device. The imaging optical system is used. The imaging optical system includes a lens or a mirror as a component. Considering one light transmitting point and one measurement target point, as shown in FIG. 2, the measurement target point 6 uses a remote imaging action by the imaging optical system 10 such as a lens. Even when 12 is separated from the sample 2, the measurement light from the specific measurement target point 6 can be received. The same applies to the light transmitting point 4, and the measuring light from the light transmitting point 16 installed apart from the sample 2 can be transmitted to the specific light transmitting point 4 by the imaging optical system 14. Regarding the light-transmitting side, when a thin light beam such as a laser beam is used as the measuring light, the light is focused from the beginning, so the image-forming optical system 14 on the light-transmitting side can be omitted. On the other hand, since the sample 2 has a light-scattering property on the light-receiving side, the imaging optical system 10 is necessarily required to receive the scattered light from the specific measurement target point 6.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an embodiment in which the present invention is applied to a practical optical CT. A thin light beam such as a laser beam is used as the measurement light 20. A mirror 22 is provided to irradiate the measurement light 20 to a predetermined light transmission point of the sample 2. The plurality of light receiving ends 12-1, 12-2, ... Are equidistantly arranged in the holder 2 in order to receive the measurement light transmitted while diffusing the sample 2 from each measurement target point on the sample surface.
4 is fixed. In the figure, two light receiving ends 12-1, 1
Although only 2-2 is shown, the holder 24 holds a larger number of light receiving ends, and each of the light receiving ends 12-1, 1
2-2, ... Are connected to photodetectors by optical fibers 26-1, 26-2 ,.

The sample 2 and the respective light receiving ends 12-1, 12-2, ...
, And convex lenses 10-1, 10-2, ... As an imaging optical system for forming respective measurement points on the sample surface on the respective light receiving ends 12-1, 12-2 ,. … Is holder 2
4 is fixed. The holder 24, the light-receiving ends 12-1, 12-2, ... Fixed to the holder 24, and the lenses 10-1, 1
0-2, ... constitute a detector unit 28. Detector unit 28, optical fibers 26-1, 26-2, ...
, And the mirror 22 are fixed to one rotating portion as a whole, and are supported so as to be rotatable around the sample 2.

Next, the operation of this embodiment will be described. Sample 2 through mirror 22 in one rotational position
The measurement light 20 is applied to the surface of the sample 2, and the output light diffused and transmitted through the inside of the sample 2 and emitted from each measurement target point is provided with a large number of optical fibers 26-1, 26-.
The light-receiving ends 12-1, 12-2, ... At this time, the respective measurement target points on the surface of the sample 2 are imaged on the corresponding light receiving ends 12-1, 12-2, ... By the lenses 10-1, 10-2 ,.

When the measurement at one rotation position is completed, the above-described measurement operation is repeated after the rotation unit rotates by a fixed angle (for example, 1/60 rotation). If this measurement is performed 60 times, measurement of all data around the sample is completed. Light receiving ends 12-1, 12-2, ... In the detector unit 28.
The number of lenses and the lenses 10-1, 10-2, ... Are not limited to those in the embodiment. The imaging optical system is not limited to a lens,
It can also be realized by a mirror such as a spherical mirror.

[0012]

According to the present invention, since the image forming optical system for forming a one-to-one image on the light receiving end of the light receiving device is provided in the present invention, the light sending and receiving device is a non-contact type in which the light sending and receiving device is not in contact with the sample.
Positional resolution equivalent to that of the contact method can be obtained. Since it is a non-contact method, it is possible to easily scan a large number of light-sending points and measurement points.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing the measurement principle of a light scatterer by a contact method.

FIG. 2 is a schematic sectional view showing the measurement principle of a light scatterer according to the present invention.

FIG. 3 is a schematic sectional view showing an example.

[Explanation of symbols]

 2 sample 4 light-sending point 6 measurement target point 10, 10-, 10-2 lens 12, 12-1, 12-2 light receiving end 20 measurement light 22 mirror 24 detector unit holder 26-1, 26-2 optical fiber 28 detector unit

Claims (1)

[Claims] 1. An irradiation unit for irradiating a light-scattering sample with measuring light, and a light receiving device for detecting measuring light emitted from a point to be measured on the surface of the sample. In the measuring device for determining the concentration and spatial distribution of the substance contained in the sample based on the detection signal of the light receiving device obtained for the target point, with the light receiving device installed away from the sample surface,
An apparatus for measuring a light scatterer, which is provided with an image forming optical system for forming an image of each measurement target point on a light receiving end of the light receiving device.